Ready for Flight: SiC Semiconductor Technology

Liebherr develops and manufactures power electronics for primary and secondary flight controls, air management systems and further electrically operated products. All current series products are equipped with standard silicon (Si) power MOSFETs or Si-IGBTs. These, however, are limited by their switching frequency and their efficiency.

Liebherr has started working with silicon carbide (SiC) semiconductors back in 2010 as part of research programs. They enable optimization and thus competitiveness of the products due to significant material benefits compared to silicon. In deep interaction with the leading SiC-manufacturers, we have followed the step-by-step improvement of SiC components until today. In this process we tackled all challenges like Electro Magnetic Interferences (EMI), components robustness and integration.

Power electronics with SiC at system level have the following advantages:

• High-voltage operation with significantly lower switching losses up to 60 %
• Stable operation also in high temperature applications > 175 °C
• Higher switching frequency leads to smaller filters and passive components
• Enhanced efficiency over whole load range
• Less cooling required at power stage level
• Reduction in volume, weight and last but not least overall system costs

SiC is already used in automotive and E-mobility applications. SiC power components reached a level of performance and reliability covering even the high aerospace requirements. With the latest generation of SiC components we were able to verify significant reduction of losses on electronic equipment level.

One major aspect of the risk-mitigation is the EMI management. In order to fulfil the EMI requirements, we have successfully implemented state-of-the-art SiC switches in a series product for verification reasons. Even with high switching speeds, the EMI values did not exceed RTCA-DO160 Cat H limits.

As a conclusion, we have reached now the technology and industrial maturity and readiness to offer Liebherr power electronics based on SiC semiconductor components. This will allow our customers to embed more lightweight, less volume and cost efficient air cooled electric systems on board the aircraft.

_{This article contains copyrighted material of Microchip Technology Incorporated replicated with permission. All rights reserved. No further replications may be made without Microchip Technology Inc.’s prior written consent.}